1. Field
The invention relates to location determination. More particularly, the invention relates to location determination using radio wave measurements and pressure measurements.
2. Background
Many conventional wireless devices rely on the Global Positioning System (GPS) to determine their present location. The GPS system uses spread spectrum signals transmitted from space that do not have much power near the earth's surface. Consequently, the signals do not generally penetrate the walls of buildings. Inside buildings, wireless device users are usually denied the use of the navigation features in their wireless devices. Moreover, even when GPS is available, the vertical location accuracy is often less than desired and unacceptably inaccurate for many applications.
There is a need for a system and method that would enable wireless devices to determine their present location while inside a building. In addition, there is a need for a system and method for more precisely determining the vertical position of a wireless device. The present invention addresses these needs as well as other needs.